Parameters Design of PLL to Enhance Inverter-grid System Stability

PLL bandwidth is a critical factor for the stability of the inverter grid-connected system in weak grids. However, there is currently a lack of a method that considers both system stability and PLL dynamic when designing PLL parameters. Therefore, this paper proposes a method for designing PLL parameters that take both factors into account. The method establishes a relationship between PLL bandwidth and phase margin, and designs the corresponding PLL parameters based on this relationship. The inverter-grid system using the designed PLL parameters can maintain stability at different inverter output power levels in weak grids. Finally, experimental results are presented to demonstrate the effectiveness of the method.